package euler

/**
 * Find the greatest product of five consecutive digits in the 1000-digit number.
	73167176531330624919225119674426574742355349194934
	96983520312774506326239578318016984801869478851843
	85861560789112949495459501737958331952853208805511
	12540698747158523863050715693290963295227443043557
	66896648950445244523161731856403098711121722383113
	62229893423380308135336276614282806444486645238749
	30358907296290491560440772390713810515859307960866
	70172427121883998797908792274921901699720888093776
	65727333001053367881220235421809751254540594752243
	52584907711670556013604839586446706324415722155397
	53697817977846174064955149290862569321978468622482
	83972241375657056057490261407972968652414535100474
	82166370484403199890008895243450658541227588666881
	16427171479924442928230863465674813919123162824586
	17866458359124566529476545682848912883142607690042
	24219022671055626321111109370544217506941658960408
	07198403850962455444362981230987879927244284909188
	84580156166097919133875499200524063689912560717606
	05886116467109405077541002256983155200055935729725
	71636269561882670428252483600823257530420752963450
 */
class Problem8 extends Problem {

  def resolve(): Unit = {
    println("Begin problem 8..")
    val number = "73167176531330624919225119674426574742355349194934" +
					"96983520312774506326239578318016984801869478851843" +
					"85861560789112949495459501737958331952853208805511" +
					"12540698747158523863050715693290963295227443043557" +
					"66896648950445244523161731856403098711121722383113" +
					"62229893423380308135336276614282806444486645238749" +
					"30358907296290491560440772390713810515859307960866" +
					"70172427121883998797908792274921901699720888093776" +
					"65727333001053367881220235421809751254540594752243" +
					"52584907711670556013604839586446706324415722155397" +
					"53697817977846174064955149290862569321978468622482" +
					"83972241375657056057490261407972968652414535100474" +
					"82166370484403199890008895243450658541227588666881" +
					"16427171479924442928230863465674813919123162824586" +
					"17866458359124566529476545682848912883142607690042" +
					"24219022671055626321111109370544217506941658960408" +
					"07198403850962455444362981230987879927244284909188" +
					"84580156166097919133875499200524063689912560717606" +
					"05886116467109405077541002256983155200055935729725" +
					"71636269561882670428252483600823257530420752963450"
	println(compareProduct(0, number, 0, calculateProduct))
  }
  def calculateProduct(i:Int, number:String): Long = {
    var sub = number.substring(i, i + 5)
    var product = 1
    sub.toCharArray().foreach( (arg:Char) => product = product * arg.toString.toInt)
    return product
  }
  
  def compareProduct(i:Int, number:String, largest:Long, product:(Int,String) => Long): Long = {
    if (i == number.length() - 4) {
    	return largest
    }
    var productResult = product(i,number)
    if (productResult < largest) productResult = largest
    compareProduct(i + 1, number, productResult, product)
  }

}